Deterioration of dental amalgams due to electrochemical reactions will be studied in vitro. The mechanism of the corrosion attack, and the effects of corrosion on the properties of various types of amalgam will be investigated. The main emphasis will be on the determination of the corrosion behavior of high copper amalgams, which exhibit higher corrosion resistance than conventional amalgams but have been shown to suffer in some cases deterioration by an unknown mechanism. Other studies will include determination of the effects of corrosion on the mechanical properties of various types of dental amalgam, investigation of the relationships between porosity, mercury content, and corrosion, and examination of the effects of aging on the corrosion properties. Corrosion test methods and conditions used in the studies of dental amalgams will be examined and evaluated.